Simplifying numerator

edit

Not strictly true :

sage: ((2*x+4)/(x^2+1)^2).expand()
2*x/(x^4 + 2*x^2 + 1) + 4/(x^4 + 2*x^2 + 1)

But :

sage: ((2*x+4)/(x^2+1)^2).expand().factor()
2*(x + 2)/(x^2 + 1)^2
sage: ((2*x+4)/(x^2+1)^2).expand().combine()
2*(x + 2)/(x^4 + 2*x^2 + 1)

Note that :

sage: ((2*x+4)/(x^2+1)^2).expand().simplify()
2*x/(x^4 + 2*x^2 + 1) + 4/(x^4 + 2*x^2 + 1)

But that :

sage: ((2*x+4)/(x^2+1)^2).expand().simplify_full()
2*(x + 2)/(x^4 + 2*x^2 + 1)

Sorry.

This is general :

sage: var("a")
a
sage: a*(2*x+4)
2*a*(x + 2)

PS : I fail to see the point...

Hello, @StevenClontz! I don't know if this solves the general case of your question, but it does solve the particular example your present. Write the following:

def latex_frac(frac):
    if frac == 0:    return '0'
    num = frac.numerator()
    den = frac.denominator()
    if den == 1:    return str(num)
    return r'\frac{' + str(num) + '}{' + str(den) + '}'

You can then call this functions like this:

latex_frac((2*x+4)/(x^2+1)^2)

which will give the result you want.

I hope this helps!